Circuit-breakers of this type are used for interrupting high line fault currents, and often require the presence of capacitance at their terminals.
Such a circuit-breaker is described in French Patent Application 90 13 176, where a capacitor and a varistor in series with a resistor are disposed inside the case, are electrically interconnected in parallel, are connected via a common first point to a first terminal, and are associated with a mechanism enabling them to be momentarily inserted in parallel with the arcing contacts during circuit-breaker disengagement or engagement.
The dispositions described in that Patent Application are suitable for capacitors having capacitances no greater than 5,000 pF.
For capacitances greater than 5,000 pF, those dispositions are not suitable, given the dimensions of the capacitors. It is difficult to house this type of capacitor inside the standard-size insulating case of the circuit-breaker.